Irrigation networks: a systems engineering approach

摘要

Gravity fed irrigation systems are essential infrastructure in support of the world's food supply. It is currently accepted that irrigated land, as compared to non-irrigated land is up to three times as economically viable, up to five times as productive, and in general leads to a more reliable and predictable supply of food. It is therefore easy to understand the enormous expansion of irrigation systems worldwide, a pursuit that is likely to continue for a few more decades. On a world scale, irrigation accounts for nearly 70 percent of all fresh water consumption (the figure for Australia is 80 percent). As the world uses 54 percent of all accessible runoff, irrigation extracts 38 percent of directly accessible yearly renewable water. This only amounts to 4 percent of the annual renewable fresh water resource, but the runoff portion is considered the more realistic limit.